Global prevalence of 4 neglected foodborne trematodes targeted for control by WHO: A scoping review to highlight the gaps

Integrated opisthorchiasis control through the EcoHealth/one health approach: 15 years of success and experiences with the Lawa model

Opisthorchis viverrini infection remains a major health problem in Northeast Thailand and the Mekong region impacting over 12 million and causing bile duct cancer. Using an EcoHealth/One Health approach at Lawa Lake in Thailand, our integrated control program achieved a substantial reduction in liver fluke prevalence from 60 % to <5 % over 15 years. Key interventions included chemotherapy, collaboratively designed health education, ecosystem modification, and community participation. Infections in intermediate hosts, Bithynia snails and Cyprinoid fish, are now undetectable. Improved community knowledge resulted in healthier practices. The "Lawa Model", a recognized model for liver fluke control, is now a training hub being scaled up in Thailand and the Mekong region. This program demonstrates how One Health strategies can address complex health and ecological challenges and aligns with WHO recommendations. The success of the Lawa Model demonstrates the efficacy of integrated One Health interventions against endemic parasitic diseases.

Hepatobiliary Platynosomosis in Black-Tufted Marmosets (Callithrix penicillata): A Lethal Threat for Wildlife and Captive Populations

Helminthic infections, particularly those caused by trematodes, pose a significant health risk to both animals and humans. This study investigates hepatobiliary platynosomosis (HP) caused by Platynosomum illiciens in black-tufted marmosets (Callithrix penicillata) in Central Brazil. Data were retrospectively collected from autopsy records at the Laboratory of Veterinary Pathology and Forensics, University of Brasília, from January 2006 to July 2021. Epidemiological, clinical, and pathological information was analyzed, including comparisons between free-ranging and captive marmosets. A total of 1596 nonhuman primate (NHP) death records were examined, with black-tufted marmosets accounting for 75.6% (1206/1595) of autopsies. HP was identified in 10.8% (131/1206) of these cases. Captive marmosets showed a higher prevalence of HP (49.6%) than free-ranging ones (6.5%). This study revealed a significant seasonal trend, with higher HP prevalence observed during the wet season until the onset of the dry season. Pathological examinations revealed severe liver and bile duct damage in fatal HP cases, including fibrosis, bile duct thickening, and the presence of flukes. Captive marmosets exhibited pronounced clinical signs, such as weight loss and apathy. Morphological and molecular analysis of sampled flukes confirmed P. illiciens infecting the marmosets. These findings underscore the substantial impact of HP on marmoset populations, particularly in captive settings. The high lethality (58% overall; 81.6% in captivity) highlights the need for improved management and preventive measures in captive environments. This study contributes to understanding HP epidemiology, clinical manifestations, and pathological outcomes, underscoring the disease's significance for the health of both free-ranging and captive NHP populations. Our findings also support the need to develop targeted strategies to mitigate the impact of HP on primate species populations.

Global, regional and national disease burden of food-borne trematodiases: projections to 2030 based on the Global Burden of Disease Study 2021

BACKGROUND

Food-borne trematodiases (FBTs), mainly encompassing clonorchiasis, fascioliasis, fasciolopsiasis, opisthorchiasis, and paragonimiasis, is a neglected public health problem, particularly in the WHO South-East Asia and the Western Pacific regions. This study evaluates the global, regional, and national disease burden of FBTs from 1990 to 2021 and projects trends to 2030, underscore the need for targeted prevention and control.

METHODS

Using the Global Burden of Disease 2021 database, the crude and the age-standardized prevalence rate (ASPR) and age-standardized prevalence disability-adjusted life years rate (ASDR) of FBTs at the global, regional and national level from 1990 to 2021 were described. The pivotal years of trend changes were identified using joinpoint regression analysis. The effects of age, period, cohort on FBTs prevalence and correlation with the sociodemographic index (SDI) was analyzed. Finally, the worldwide disability-adjusted life years (DALYs) for FBTs, projected up to 2030 using the Bayesian age-period-cohort model, were analyzed.

RESULTS

In 2021, 44,466,329 FBTs cases [95% uncertainty interval (UI): 40,017,217, 50,034,921], and 998,028 DALYs [95% UI: 569,766, 1,638,112] were estimated across 17 countries. The Western Pacific region exhibited the highest ASPR and ASDR, with the values of 1649.26 (95% UI: 1461.95, 1881.64) and 36.54 (95% UI: 19.77, 64.16), respectively. From 1990 to 2021, Lao PDR, Thailand, and the Philippines showed the most substantial declines in FBTs, while Kazakhstan had the largest average annual percentage change in DALYs (- 6.60, 95% UI: - 7.10, - 6.10). High-middle and middle SDI countries exhibited higher burden, with ASDR values of 28.03 (95% UI: 15.41, 48.73) and 16.63 (95% UI: 9.32, 27.68), respectively. The disease burden was greater among males, peaking in the 50-59 age group. The projected ASDR in 2030 is 13.10 for males and 8.40 for females.

CONCLUSIONS

FBTs remain a public health threat, with the global ASDR projected to remain stable, showing only a slight decrease by 2030. Low-income countries face ambiguous mortality rates and underestimated disease burdens, highlighting the need for improved surveillance. To achieve the 2030 NTD goal, comprehensive surveillance and integrated strategies derived using a One Health approach should be prioritized to control FBTs effectively.

A multidisciplinary analysis of over 53,000 fascioliasis patients along the 1995-2019 countrywide spread in Vietnam defines a new epidemiological baseline for One Health approaches

Fascioliasis, only foodborne trematodiasis of worldwide distribution, is caused by Fasciola hepatica and F. gigantica, liver flukes transmitted by freshwater snails. Southern and southeastern Asia is an emerging hot spot of F. gigantica, despite its hitherto less involvement in human infection. In Vietnam, increasing cases have been reported since 1995, whereas only sixteen throughout 1800-1994. A database was created to include epidemiological data of fascioliasis patients from the 63 Vietnam provinces throughout 1995-2019. Case profiles were based on serology, symptoms, eosinophilia, imaging techniques, stool egg finding, and post-specific-treatment recovery. Radio broadcasting about symptoms and costless diagnosis/treatment led patients to hospitals after symptom onset. Yearly case numbers were modelled and spatio-temporally analyzed. Missing data and confounders were assessed. The countrywide spread has no precedent. It started in the central coast, including 53,109 patients, mostly adults and females. Seasonality, linked to vegetable consumption, peaks in June, although the intensity of this peak differs according to relief/climatic zones. Incidence data and logistic regression curves are obtained for the first time in human fascioliasis. Fasciolid hybrids accompanying the spreading F. gigantica flukes, and climate change assessed by risk index correlations, are both ruled out as outbreak causes. Human-guided movements of livestock from an original area prove to be the way used by fasciolids and lymnaeid vectors to expand geographically. Radix viridis, a highly efficient transmitting and colonizing vector, played a decisive role in the spread. The use of irrigated crop fields, widely inhabited by R. viridis, for livestock grazing facilitated the transmission and spread of the disease. General physician awareness and diagnostic capacity improvement proved the successful impact of such knowledge transfer in facilitating and increasing patient infection detection. Information, education and communication to the public by radio broadcasting demonstrated to be very helpful. Fasciola gigantica is able to cause epidemic and endemic situations similar to F. hepatica. The magnitude of the human outbreak in Vietnam is a health wake-up call for southern and southeastern countries of Asia which present the highest human population densities with increasing food demands, uncontrolled livestock inter-country exchange, foreign import practices, and monsoon's increasing climate change impact.

Study on the prevalence of trematode cercariae infection in freshwater snails in Manipur, India

Freshwater snails act as first intermediate carriers for numerous trematodes, which can induce sickness in both humans and animals. In Manipur, various species of freshwater snails have been discovered to harbor trematode infections. In this study, we aimed to assess the prevalence of different varieties of freshwater snail species serving as the primary, intermediate hosts for various trematodes in endemic areas of paragonimiasis, a disease caused by Paragonimus trematodes found in two separate regions, Luwangsangbam matai in the Imphal East district and Moreh in the Tengnoupal district of Manipur province. These areas are known to be endemic for human paragonimiasis. We examined 4074 snails, including Bortia costula, Filopaludina bengalensis, Paludomous pustulosa, Indoplanorbis exustus using the shedding and crushing method. Our findings revealed that 43(1.05%) snails were positive for different trematode cercariae. Specifically, Bortia costula was infected with Fasciola spp, and unidentified cercariae, while Filopaludina bengalensis and Paludomous pustulosa harboured Gymnacephalous and Echinostomous cercariae. Interestingly, Indoplanorbis exustus did not show any infection with trematode cercariae. A strong association was found between these types of snail species and cercarial infection. Furthermore, statistical analysis did not demonstrate a significant correlation between the geographical location and cercarial infection among snail species. Our study provides the current status of the prevalence of trematode cercarial infection in these snails, offering insights into disease transmission dynamics and the role of snails in paragonimiasis epidemiology.

Unveiling the Transmission Potential of Opisthorchis viverrini and Intestinal Helminths Along the Thailand-Laos Border in Thailand

AIMS

In pursuit of enhancing prevention efforts for the notably high endemic Opisthorchis viverrini infection in lower Mekong sub-region countries, particularly Thailand and Laos, this cross-sectional study investigated the transmission potential of O. viverrini and other intestinal helminths along the Thailand-Laos border in seven Thai villages.

METHODS AND RESULTS

Human and pet faecal samples, Bithynia snails and cyprinid fish were analysed for helminth infections. Additionally, a questionnaire survey assessed relevant risk factors among the human population. Two groups of helminth infections were detected in humans: foodborne infections (FBIs) including O. viverrini, minute intestinal flukes (MIFs), and Taenia spp., and soil-transmitted infections (STIs) including hookworm and Strongyloides stercoralis, with prevalence rates of 7.4%, 0.5%, 2.5%, 0.5%, 2.5% and 3%, respectively. Smoking was identified as a risk factor for O. viverrini infection [adjusted odds ratios (ORa) = 3.12, 95% confidence intervals (CI): 1.33-7.30, p = 0.009] and FBIs (ORa = 2.47, 95% CI: 1.14-5.33, p = 0.022), while male was a risk factor for FBIs (ORa = 2.62, 95% CI: 1.16-5.94, p = 0.021). In dogs, hookworm, Toxocara spp., Spirometra mansoni, Trichuris vulpis and Hymenolepis diminuta were identified with prevalence rates of 35.6%, 8.1%, 8.1%, 1.2% and 1.2%, respectively. In cats, hookworm, Toxocara spp., S. mansoni, Strongyloides spp., Platynosomum fastosum, MIFs and H. diminuta were identified with prevalence rates of 50%, 17.9%, 10.7%, 7.1%, 3.6%, 3.6% and 3.6%, respectively. Bithynia snails showed 2% virgulate and 0.7% unknown cercariae infections, while among 19 cyprinid fish species, only unknown metacercariae were found.

CONCLUSIONS

Our findings underscore the necessity of an integrated approach following the One Health concept to effectively combat these parasitic diseases while addressing human, animal and environmental health.

An immunochromatographic test using whole blood for rapid diagnosis of human paragonimiasis and its diagnostic usefulness

Paragonimiasis is a harmful food-borne zoonosis caused by lung flukes of the genus Paragonimus. The disease is found on most continents, several million people are at risk of infection, and it is a re-emerging disease in developing countries. The gold standard for diagnosis of pulmonary paragonimiasis requires the finding of eggs in sputa and/or fecal samples. In ectopic paragonimiasis cases, eggs are typically not seen, and supportive information is required such as a history of eating freshwater crabs or crayfishes, radiographic findings and immunological tests. Here, we developed a proof of concept based on lateral flow assay, an immunochromatographic test kit, named the paragonimiasis whole-blood test kit, for detection of specific IgG antibody in simulated whole-blood samples (WBSs) using worm excretory-secretory antigens to diagnose human paragonimiasis. The laboratory diagnostic values of this kit were compared with the detected IgG in serum samples. In simulated WBSs, the diagnostic sensitivity and specificity were 97.8 % and 96.1 %, respectively, while for serum samples, these values were 100.0 % and 94.8 %, respectively. The comparative IgG antibody detections whether a result was positive or negative between simulated WBSs and serum samples did not differ significantly with a concordance of 97.8 % in laboratory conditions using a circumscribed set of samples. The tool is fast and easy to use. The next step involves observing and evaluating native whole blood samples and using specific recombinant antigens need to be evaluated for support diagnosis of paragonimiasis caused by P. heterotremus, P. westermani and P. miyazakii at the bedside or at local and remote hospitals with limited facilities. It will also be valuable for epidemiological surveys in Asia where paragonimiasis is endemic.

Global burden of zoonotic infectious diseases of poverty, 1990-2021

BACKGROUND

The zoonotic infectious diseases of poverty (zIDPs) are a group of diseases contributing to global poverty, with significant impacts on a substantial population. This study aims to describe the global, regional, and national burden of zIDPs-schistosomiasis, cystic echinococcosis, cysticercosis, and food-borne trematodiases (FBTs)-to support policy making and resource allocation for their control and elimination.

METHODS

Data of zIDPs from the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2021 were retrieved from 1990 to 2021. The age-standardized prevalence rate (ASPR), age-standardized mortality rate (ASMR), and age-standardized disability-adjusted life-year (DALY) rate were described and the estimated annual percentage changes (EAPCs) were calculated to quantify their burden and temporal trends. Spearman correlation analysis was conducted to examine the relationship between age-standardized rates and Socio-demographic Index (SDI).

RESULTS

In 2021, these zIDPs exhibited a certain level of ASPRs and age-standardized DALY rates, while maintaining relatively low ASMRs. Noticeably, schistosomiasis presented the highest ASPR of 1914.299 (95% UI: 1378.920, 2510.853 per 100,000 population) and an age-standardized DALY rate of 21.895 (95% UI: 12.937, 37.278 per 100,000 population) among the zIDPs. The tapestry of burden-woven predominantly through low and lower-middle SDI regions-stretched across Africa, Latin America, and parts of Asia. From 1990 to 2021, a kaleidoscopic shift was observed globally as ASPRs, ASMRs, and age-standardized DALY rates declined significantly, as reflected by the EAPC values. Negative correlations were observed between the ASPRs, ASMRs, age-standardized DALY rates of schistosomiasis (r value = - 0.610, - 0.622 and - 0.610), cystic echinococcosis (- 0.676 of ASMR, - 0.550 of age-standardized DALYs), cysticercosis (- 0.420, - 0.797 and - 0.591) and the SDI. In contrast, a slight positive correlation was noted between the ASPR, age-standardized DALY rates of FBTs and SDI with r value of 0.221 and 0.213, respectively.

CONCLUSION

The burden of zIDPs declined across almost all endemic regions from 1990 to 2021, yet still predominated in low and low-middle SDI regions. Substantial challenges exist to achieve the goal of control and elimination of zIDPs, and integrated approaches based on One Health need to be strengthened to improve health outcomes.

Amphimeriasis in Ecuador-Prevalence, Knowledge, and Socio-Cultural Practices Among Indigenous Chachi and Montubios Populations: A Mixed-Methods Cross-Sectional Study

Amphimerus, a liver fluke, is the causative agent of amphimeriasis, a foodborne disease acquired thought the consumption of infected raw or undercooked river fish-a practice embedded in traditional culinary customs. Amphimeriasis represents a significant public health issue and has been endemic in Ecuador since 2011, particularly among the Chachi Amerindians and Montubios populations residing in tropical ecoregions. By employing a mixed-methods research design, we conducted a community-based, cross-sectional study. A survey comprising of 63 questions on KAP was administrated in person to community members, health personnel, and academic staff in the two populations. Additionally, 67 semi-structured interviews were performed. Microscopy was achieved on 273 human and 80 dog fecal samples to detect Amphimerus eggs. A total of 86 questionnaires (54 Chachi) and 67 interviews (44 Chachi), out of 300 residents, were completed. Among the respondents, 31.4% were aware of Amphimerus, locally referred to as "liver worm". Although 79.1% reported not consuming raw fish, most admitted eating raw fish with lime juice and salt, a preparation known as "curtido", and 59.3% reported consuming smoked fish. Here, 86.1% of participants considered "liver worm" a serious disease, and 55.8% recognized raw or marinated fish as a potential transmission route. The Chachi showed a preference for smoked fish, whereas the Montubios favoured "curtido". The prevalence of Amphimerus infection was 23% in humans and 16.2% in dogs. Differences in KAP were observed between infected and non-infected individuals. Local health and academic personnel demonstrated insufficient knowledge about amphimeriasis. Some religious individuals refrained from participating, stating that they were "with God". Despite the high prevalence of Amphimerus infection in both humans and dogs, knowledge about the parasite, the disease, and its transmission routes remains limited. Health education initiatives should be designed to modify the population's KAP. It is crucial for national and local health authorities, as well as religious leaders, to be informed and actively involved in the prevention and control of amphimeriasis.

Parasites of the liver: A global problem?

Parasitic liver diseases can be caused by trematodes, cestodes, nematodes, and protozoa. This pathology is significant because millions of people in different parts of the world have liver parasites, which can manifest themselves in the development of inflammation, liver cysts, cholecystitis, cholelithiasis, pancreatitis and liver cirrhosis that are often threatening their lives. The International Agency for Research on Cancer considers three species of trematodes, Schistosoma haematobium, Opisthorchis viverrini and Clonorchis sinensis, to be carcinogens. Complex modern examination methods, in some cases including extensive screening of large populations, are required for diagnosing liver parasites. Treatment of parasitic liver diseases is differentiated and can involve a combination of surgical and therapeutic measures. There is no doubt that the clinical and epidemiological scale allows one to regard parasitic liver diseases as a global healthcare problem.

Infection and biogeographical characteristics of Paragonimus westermani and P. skrjabini in humans and animal hosts in China: A systematic review and meta-analysis

BACKGROUND

Paragonimiasis, primarily caused by Paragonimus westermani and P. skrjabini in China, is a common food-borne parasitic zoonosis. However, the national distribution of Paragonimus spp. infection and its associated environmental determinants remain poorly understood. In this paper, we summarize the infection of P. westermani and P. skrjabini and describe key biogeographical characteristics of the endemic areas in China.

METHODS

Data on Paragonimus infection in humans and animal hosts were extracted from eight electronic databases, including CNKI, CWFD, Chongqing VIP, SinoMed, Medline, Embase, PubMed, and Web of Science. A random-effects meta-analysis model was used to estimate the pooled prevalence. All survey locations were georeferenced and plotted on China map, and scatter plots were used to illustrate the biogeographical characteristics of regions reporting Paragonimus infection.

RESULTS

A total of 28,948 cases of human paragonimiasis have been documented, with 2,401 cases reported after 2010. Among the 11,443 cases with reported ages, 88.05% were children or adolescents. The pooled prevalence of P. skrjabini is 0.45% (95% CI: 0.27-0.66%) in snails, 31.10% (95% CI: 24.77-37.80%) in the second intermediate host, and 20.31% (95% CI: 9.69-33.38%) in animal reservoirs. For P. westermani, the pooled prevalence is 0.06% (95% CI: 0.01-0.13%) in snails, 52.07% (95% CI: 43.56-60.52%) in the second intermediate host, and 21.40% (95% CI: 7.82-38.99%) in animal reservoirs. Paragonimus are primarily distributed in regions with low altitude, high temperature, and high precipitation. In northeastern China, only P. westermani infections have been documented, while in more southern areas, infections of both P. westermani and P. skrjabini have been reported.

CONCLUSIONS

Paragonimiasis remains prevalent in China, particularly among children and adolescents. Variations exist in the intermediate hosts and geographical distribution of P. westermani and P. skrjabini. Additionally, altitude, temperature, and precipitation may influence the distribution of Paragonimus.

Expression of Transposable Elements throughout the Fasciola hepatica Trematode Life Cycle

BACKGROUND

Transposable elements (TEs) are major components of eukaryotic genomes. The extensive body of evidence suggests that although they were once considered "genomic parasites", transposons and their transcripts perform specific functions, such as regulation of early embryo development. Understanding the role of TEs in such parasites as trematodes is becoming critically important. Fasciola hepatica, a parasite affecting humans and livestock, undergoes a complex life cycle in diverse environments and hosts, and knowledge about its life cycle regulation is scarce so far.

METHODS

We summarized the data regarding the repetitive elements in F. hepatica and conducted bulk RNA-seq analysis across its life cycle stages. TE expression profiles were analyzed, focusing on differential expression and potential homology with previously described long non-coding RNAs (lncRNAs).

RESULTS

Differential expression analysis revealed stage-specific TE transcription patterns, notably peaking during egg and metacercariae stages. Some TEs showed homology with known lncRNAs and contained putative transcription factor binding sites. Interestingly, TE transcription levels were highest in eggs and metacercariae compared to adults, suggesting regulatory roles in trematode life cycle transitions.

CONCLUSIONS

These findings suggest that TEs may play roles in regulating trematode life cycle transitions. Moreover, TE homology with lncRNAs underscores their significance in gene regulation.

Global distribution of zoonotic digenetic trematodes: a scoping review

BACKGROUND

Digenetic trematodes, including blood flukes, intestinal flukes, liver flukes, lung flukes, and pancreatic flukes, are highly diverse and distributed widely. They affect at least 200 million people worldwide, so better understanding of their global distribution and prevalence are crucial for controlling and preventing human trematodiosis. Hence, this scoping review aims to conduct a comprehensive investigation on the spatio-temporal distribution and epidemiology of some important zoonotic digenetic trematodes.

METHODS

We conducted a scoping review by searching PubMed, Web of Science, Google Scholar, China National Knowledge Infrastructure, and Wanfang databases for articles, reviews, and case reports of zoonotic digenetic trematodes, without any restrictions on the year of publication. We followed the inclusion and exclusion criteria to identify relevant studies. And relevant information of the identified studies were collected and summarized.

RESULTS

We identified a total of 470 articles that met the inclusion criteria and were included in the review finally. Our analysis revealed the prevalence and global distribution of species in Schistosoma, Echinostoma, Isthmiophora, Echinochasmus, Paragonimus, Opisthorchiidae, Fasciolidae, Heterophyidae, and Eurytrema. Although some flukes are distributed worldwide, developing countries in Asia and Africa are still the most prevalent areas. Furthermore, there were some overlaps between the distribution of zoonotic digenetic trematodes from the same genus, and the prevalence of some zoonotic digenetic trematodes was not entirely consistent with their global distribution. The temporal disparities in zoonotic digenetic trematodes may attribute to the environmental changes. The gaps in our knowledge of the epidemiology and control of zoonotic digenetic trematodes indicate the need for large cohort studies in most countries.

CONCLUSIONS

This review provides important insights into the prevalence and global distribution of some zoonotic digenetic trematodes, firstly reveals spatio-temporal disparities in these digenetic trematodes. Countries with higher prevalence rate could be potential sources of transmitting diseases to other areas and are threat for possible outbreaks in the future. Therefore, continued global efforts to control and prevent human trematodiosis, and more international collaborations are necessary in the future.

Bioclimatic analysis and spatial distribution of fascioliasis causative agents by assessment of Lymnaeidae snails in northwestern provinces of Iran

BACKGROUND

Snails of the Lymnaeidae family are the intermediate hosts of Fasciola species, the causative agents of fascioliasis. The purpose of this study was to determine the prevalence of Fasciola species in lymnaeid snails and to investigate the association of geoclimatic factors and Fasciola species distribution in northwestern provinces of Iran using geographical information system (GIS) data.

METHODS

A total of 2000 lymnaeid snails were collected from 33 permanent and seasonal habitats in northwestern Iran during the period from June to November 2021. After identification by standard morphological keys, they were subjected to shedding and crushing methods. Different stages of Fasciola obtained from these snails were subjected to the ITS1 polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method for species identification. The associations of weather temperature, rainfall, humidity, evaporation, air pressure, wind speed, elevation, and land cover with the distribution of Fasciola species were investigated. Geographical and statistical analysis was performed using ArcMap and SPSS software, respectively, to determine factors related to Fasciola species distribution.

RESULTS

Of the 2000 snails collected, 19 were infected with Fasciola hepatica (0.09%), six with F. gigantica (0.03%), and 13 with other trematodes. Among geoclimatic and environmental factors, mean humidity, maximum humidity, and wind speed were significantly higher in areas where F. hepatica was more common than F. gigantica. The altitude of F. hepatica-prevalent areas was generally lower than F. gigantica areas. No significant relationship was observed between other investigated geoclimatic factors and the distribution of infected snails.

CONCLUSIONS

The present study showed the relationship of humidity and wind speed with the distribution of snails infected with F. hepatica or F. gigantica in the northwestern regions of Iran. In contrast to F. gigantica, F. hepatica was more prevalent in low-altitude areas. Further research is recommended to elucidate the relationship between geoclimatic factors and the presence of intermediate hosts of the two Fasciola species.

Effectiveness of health education in improving knowledge, attitude and practice related to foodborne zoonotic trematodes in Vietnam, with a particular focus on Clonorchis sinensis

OBJECTIVE

Foodborne zoonotic trematodes (FZT), which infect the liver, lungs and intestines of humans, are an emerging public health concern in tropical countries including Vietnam. In northern Vietnam, Clonorchis sinensis is recognised as the most important species of the FZT. Up to now, small-scale studies conducted in the country have indicated that health education could improve participants' knowledge and practices related to clonorchiasis, however strong evidence is still lacking. We conducted an intervention trial between 2020 and 2021 in four communes in Yen Bai and Thanh Hoa province, aiming to evaluate the impact of an extended educational package on knowledge, attitude and practices related to clonorchiasis, as well as on knowledge on the large liver fluke and minute intestinal flukes.

METHODS

To this end, baseline and post-intervention questionnaires were conducted. Generalised estimating equations models were run to analyse the impact of the intervention on knowledge, attitudes and practices over time in the intervention versus control group. Finally, 172 people in the intervention group and 162 in the control group were included for analysis.

RESULTS

Results demonstrated that the intervention significantly improved clonorchiasis knowledge, attitudes and practices, with higher odds for a correct knowledge response (odds ratio (OR) = 2.80, 95% confidence interval (CI) = 1.84-4.27, p-value < 0.001), increased average mean attitude score (mean = 0.363, 95%CI = 0.182-0.544, p-value < 0.001), and a reduced odds of consuming raw fish (OR = 0.15, 95%CI = 0.06-0.40, p = 0.002) in the intervention group compared to the control group post-intervention versus baseline. Additionally, participants in the intervention group exhibited enhanced basic knowledge of the large liver fluke and minute intestinal flukes post-intervention.

CONCLUSIONS

These findings demonstrate the potential of health education programs in preventing clonorchiasis in endemic areas, emphasising the importance of continued health education as a critical component of integrated control programs for clonorchiasis.

Effects of temperature on the life history traits of intermediate host snails of fascioliasis: A systematic review

BACKGROUND

The impact of climate change has led to variations in various biological processes, leading to altered transmission dynamics of infectious diseases, including snail-borne diseases (SBDs). Fascioliasis is one of the neglected zoonotic tropical snail-borne diseases caused by the trematode of the genus Fasciola. This review focused on laboratory experimental and model studies that evaluate the potential effect of temperature change on the ecology and biology of the intermediate host snails (IHS) of Fasciola.

METHODS

A literature search was conducted on Google Scholar, EBSCOhost, and PubMed databases using predefined medical subject heading terms, Boolean operators, and truncation symbols in combination with direct keywords: Fasciolosis AND Temperature, Lymnaea OR Austropeplea OR Radix OR Galba OR Fossaria OR Pseudosuccinea AND growth, fecundity, AND survival at the global scale. Other search terms used were (Fascioliasis AND Temperature), (Lymnaea AND Temperature), (Austropeplea AND Temperature), (Fossaria AND Temperature), (Galba AND Temperature), (Pseudosuccinea AND Temperature), and (Radix AND Temperature).

RESULTS

The final synthesis included thirty-five published articles. The studies reviewed indicated that temperature rise may alter the distribution, and optimal conditions for breeding, growth, and survival of IHS, ultimately resulting in changing the transmission dynamics of fascioliasis. The literature also confirmed that the life history traits of IHS and their interaction with the liver fluke parasites are driven by temperature, and hence climate change may have profound outcomes on the population size of snails, parasite density, and disease epidemiology.

CONCLUSION

We concluded that understanding the impact of temperature on the growth, fecundity, and survival of IHS may broaden our knowledge of the possible effects of climate change and hence inform fascioliasis control programs.

One Health for fascioliasis control in human endemic areas

Fasciola hepatica and F. gigantica are liver flukes causing fascioliasis, a worldwide zoonotic, complex disease. Human infection/reinfection occurs in endemic areas where preventive chemotherapy is applied, because of fasciolid transmission ensured by livestock and lymnaeid snail vectors. A One Health control action is the best complement to decrease infection risk. The multidisciplinary framework needs to focus on freshwater transmission foci and their environment, lymnaeids, mammal reservoirs, and inhabitant infection, ethnography and housing. Local epidemiological and transmission knowledge furnished by previous field and experimental research offers the baseline for control design. A One Health intervention should be adapted to the endemic area characteristics. Long-term control sustainability may be achieved by prioritizing measures according to impact depending on available funds.